Remove unused mixins

CHANGELOG

@@ -14,6 +14,7 @@ v 8.12.0 (unreleased)
   - Remove Gitorious import
   - Add Sentry logging to API calls
   - Automatically expand hidden discussions when accessed by a permalink !5585 (Mike Greiling)
+  - Remove unused mixins (ClemMakesApps)
   - Fix groups sort dropdown alignment (ClemMakesApps)
   - Add horizontal scrolling to all sub-navs on mobile viewports (ClemMakesApps)
   - Fix markdown help references (ClemMakesApps)

app/assets/stylesheets/framework/mixins.scss

@@ -9,22 +9,6 @@
   border-radius: $radius;
 }
 
-@mixin border-radius-left($radius) {
-  @include border-radius($radius 0 0 $radius)
-}
-
-@mixin border-radius-right($radius) {
-  @include border-radius(0 0 $radius $radius)
-}
-
-@mixin linear-gradient($from, $to) {
-  background-image: -webkit-gradient(linear, 0 0, 0 100%, from($from), to($to));
-  background-image: -webkit-linear-gradient($from, $to);
-  background-image: -moz-linear-gradient($from, $to);
-  background-image: -ms-linear-gradient($from, $to);
-  background-image: -o-linear-gradient($from, $to);
-}
-
 @mixin transition($transition) {
   -webkit-transition: $transition;
   -moz-transition: $transition;
@@ -38,14 +22,6 @@
  * Mixins with fixed values
  */
 
-@mixin shade {
-  @include box-shadow(0 0 3px #ddd);
-}
-
-@mixin solid-shade {
-  @include box-shadow(0 0 0 3px #f1f1f1);
-}
-
 @mixin str-truncated($max_width: 82%) {
   display: inline-block;
   overflow: hidden;
@@ -94,23 +70,6 @@
   }
 }
 
-@mixin input-big {
-  height: 36px;
-  padding: 5px 10px;
-  font-size: 16px;
-  line-height: 24px;
-  color: #7f8fa4;
-  background-color: #fff;
-  border-color: #e7e9ed;
-}
-
-@mixin btn-big {
-  height: 36px;
-  padding: 5px 10px;
-  font-size: 16px;
-  line-height: 24px;
-}
-
 @mixin bulleted-list {
   > ul {
     list-style-type: disc;